Steroido(16 alpha, 17 alpha-d)-oxazolines and their preparation

ABSTRACT

WHEREIN X represents hydrogen or halo; Y represents H(OH) or O; or X and Y together represent a double bond between the carbon atoms in 9 and 11 positions; R represents H or lower acyl; and R&#39;&#39; represents lower alkyl.   Steroido(16 Alpha ,17 Alpha -d)oxazolines of the formula

United States Patent 1 Nathansohn Aug. 28, 1973 STEROIDO(16 ALPHA, l7

ALPHA-D)-OXAZOLINES AND THEIR PREPARATION [75] Inventor: Giangiacomo Nathansohn, Milan,

Italy [73] Assignee: Gruppo Lepetit S.p.A., Milan, Italy [22] Filed: June 24, 1971 [21] Appl. No.: 156,538

[52] US. Cl. 260/239.55, 260/397.45, 260/349 [51] Int. Cl. C070 173/00, C070 173/10 [58] Field of Seareh 260/239.55

[56] References Cited UNITED STATES PATENTS 3,631,033 12/1971 Nathansohn et al 260/239.55

Primary ExaminerElbert L. Roberts Attorney-Theodore Post et al.

[57] ABSTRACT Steroido[ 16a, 1 7a-d]oxazolines of the formula cmon I ,0 -R ,N Y I f' wherein X represents hydrogen or halo; Y represents H(OH) or O; or X and Y together represent a double bond between the carbon atoms in 9 and l 1 positions; R represents H or lower acyl; and R represents lower alkyl.

7 Claims, No Drawings STEROIDO(16 ALPHA, 17 ALPHA-D)-OXAZOLWES AND THEIR PREPARATION STATEMENT OF THE INVENTION CHEG R wherein X represents hydrogen or halo; Y represents H(OH) or O; or X and Y together represent a double bond between the carbon atoms in 9 and 11 positions;

R represents H or lower acyl; and R represents lower alkyl. By lower alkyl is meant a l to 4 carbon alkyl group, such as, for example, methyl, ethyl, propyl or butyl; by lower acyl is meant a 2 to 4 carbon acyl group, such as, for example, acetyl, propionyl or butyryl; and by halo is meant fluoro, chloro, bromo or iodo.

BACKGROUND OF THE INVENTION In a paper published in Gazzetta Chimica ltaliana 95, 1338, 1965, Nathansohn et al. describe pregnanooxazoline derivatives in which the oxygen and the nitrogen atoms of the oxazoline moiety have either a 170:, 160:- or 173, l6fl-configuration. In both cases, howevr, the oxygen atom is attached to the 16 carbon atom while the nitrogen atom is attached to the 17 carbon atom.

The present invention provides a method for preparing novel compounds wherein the oxazoline ring is fused with ring D of the steroid nucleus in such a way that the nitrogen atom is attached to the l6a-position and the oxygen atom is attached to the l7a-position of the steroid nucleus. To prepare these novel compounds, the introduction of a l6a-amino group, or a group equivalent to it, in the pregnane ring was needed. This represented a previously insurmountable difficulty since it was known from the prior art that the reactions for introducing a convenient precursor of the amino group led to undesired compounds. Thus, for instance, ring opening by azide ions of 1611-, 17a-epoxides of the pregnane series gives only lfifi-azido derivatives, while ring opening of 165-, 17B-epoxides gives 17aand 17B-azido derivatives.

DESCRIPTION OF THE PREFERRED EMBODIMENTS We have now found that a convenient method for introducing a loci-amino group in the pregnane nucleus is by way of l6B-chloroamino formation. In this method, 33-, l7B-dihydroxy-l6B-azido-5a-pregnane- 11,20-dione is used as a starting material. This compound, after diacylation in 3- and l7-positions is reduced with Raney nickel under a hydrogen atmosphere to the corresponding l6B-amino-3B,l7a-dihydroxy- Sa-pregnane-l 1,20-dione-3, 1 7-diacylate. The 163- amino pregnane is then converted by treatment with N-chlorosuccinimide or t-butyl hypochlorite into the l6B-chloroamino compound which, after heating in dimethyl formamide (DMF) in the presence of a potassium salt of a 2 to 4 carbon monocarboxylic acid, sur- 2 prisingly gives l6-acylamido-3B, l 7a-dihydroxy-5apregn-lS-en-l1,20-dione-3-acylate according to the following scheme:

where the symbol Ac stands for lower acyl. During this step, hydrogen chloride is eliminated and the lower acyl group migrates from the oxygen to the nitrogen atom. At the same time, a double bond between C and C is formed. The resulting pregnl S-en derivative is then hydrogenated, using palladiated charcoal as a catalyst, to give a mixture of -70 percent of the 16aamidmderivative and 30-35 percent of the l6B-amidoderivative. The ratio of these two compounds is determined by nuclear magnetic resonance (NMR) absorption measurements. The lGa-amido compound may be obtained in pure form by crystallization from methanol. The pure a-amido or, alternatively, the a,B-mixture is then cyclized by refluxing a solution thereof in an appropriate organic solvent, such as, for instance, benzene, toluene or xylene.

When the a,B-mixture is used, the separation of the steroido l6a,l 7a-dloxazoline does not present particular difficulties since only the a-isomer undergoes cyclization while the l6B-amido steroid does not. The pure steroido [l6a,l7a-d]oxazolines are obtained in this case by chromatographing, the solution of the crude mixture on silica gel. The following scheme summarizes the ring closure step:

reflux Reduction of the 1 l-keto to an 1 IB-hydroxy group is then easily carried out with sodium borohydride as reductant, first protecting the 20-keto group by transforming it into the corresponding semicarbazone in the usual way. During the reduction step, the hydrolysis of 5 the 3B-acy1oxy group is promoted by the strongly basic aqueous solution of sodium borohydride. The soobtained 1 1B-hydroxy-ZO-keto-pregnane-[ 16a,1 7adloxazoline semi-carbazone is hydrolyzed by treatment with hydrochloric acid. Under these conditions, an elimination reaction takes place simultaneously with double bond formation between positions 9 and 11. The reaction pathway is outlined in the following scheme:

t -alkyi on; N

\l/ ts (DNBBH:

C IhOAc v To obtain 9a-ha1o-1lB-hydroxy derivatives, the following procedures are utilized: a. the l,4,9(11)-triene derivative is treated with N- bromoacetamide to give the 9a-bromo-l lfi-hydroxy steroid;

b. the latter is dehydrohalogenated with potassium acetate in an anhydrous solvent and c. the so-obtained 9B, llB-epoxysteroid is opened with hydrogen fluoride.

The three above-mentioned steps are carried out in usual ways with reactions which are familiar to steroid chemists.

Representative compounds which are prepared by procedures as described above are the following:

1 ,4-pregn adiene-Qa-fluoro-l 1B,21-diol-3,20-

dione[ 1601,17a-d]-2'-methyloxazoline-21- butyrate;

1,4-pregnadiene-9a-fluoro-1 1B,21-diol-3,20-

dione[ 1601,17a-d]-2-methyloxazoline-21 -acetate', 1 ,4-pregnadiene-9a-fluoro-1 lB,21-diol-3 ,20-

dione[1601,17a-d]-2-ethyloxazoline-2l-acetate; 1,4-pregnadiene-9a-fluoro-l 1B,21-diol-3,20- dione[1601,17a-d]-2-ethyloxazo1ine-2l-acetate;

1 ,4-pregnadiene-9a-fluoro-1 113,21-diol-3 ,20-

dione[ l6a,1 7a-d]-2'-butyloxazoline-21 -acetate; 1 ,4-pregnadiene-9a-f1uoro-21 -o1-3 ,1 l ,20-

trione[ 1611,17a-d]-2-methyloxazoline-2l-acetate; 1 ,4-pregnadiene-9a-fluoro-2 1 -ol-3 ,1 1 ,20-

triene{ 1601,17a-d]-2'-methy1oxazoline-2l-acetate; 1 ,4-pregnadiene-9a-fluoro-21-ol-3 ,1 1 ,20-

trione[ 16a,17a-d]2 -ethyloxazoline-2 l-acetate; 1 ,4-pregnadiene-9a-fluoro-21-o1-3 ,1 1 ,20-

trione[ 16a,17a-d]-2-ethyloxazoline-2 1 -acetate; 1,4-pregnadiene-9oz-fluoro-2 l -ol-3 ,1 1,20-

trione[ 1 601,1 7a-d1-2 '-buty1oxazoline-21-acetate; 1,4-pregnadiene-9a-fluoro-21-o1-3,1 1 ,30-

trione[ 1601,] 7a-d]-2-butyloxazoline-21-acetate; 1,4-pregnadiene-1 1 ,21-diol-3,20-dione[ 1 601,1 7a-d]- 2 '-methyloxazoline-21-acetate;

1,4-pregnadiene-l 1,2 l -dio l-3,20-dione[ 16a, 1 7a-dl- 2-ethyloxazoline-2 i -acetate;

1,4-pregnadiene-1 1,21 -dio1-3,20-dione[ 16a,17a-d]- 2-butyloXazoline-2 1 acetate; 1,4-pregnadiene-21-ol-3,1 1,20-trione[16a,l7a-d]- 2 '-methyloxazoline-2 1 -proprionate; 1,4-pregnadiene-21-ol-3 ,l 1,20-trione[ 16a,17ct-d]- 2'-butyloxazoline-21-acetate.

All of the compounds of the present invention exhibit a high degree of anti-inflammatory activity associated with a low order of toxicity. Those compounds which have 9-fluoro substitution are most effective. For example, the compound 1,4-pregriadiene-9a-fluoro- 1 1,6,21-diol-3,20-dione-[ l601,17a-d]-2-methyloxazo- 1ine-21-acetate, showed an activity in the granuloma pellet test in rats about 10 times that of hydrocortisone. The antigranulomatous activity was evaiuated on adrenalectomized rats after oral administration of a dose of 0.30 mg/kg of the compound. Under these conditions, a decrease of the granuloma was found to be of about 30 percent while 3 mg/kg of hydrocortisone reduced the formation of the granulorna by 32 percent.

The inventive compounds also have a glucorticoid activity. In representative experiments carried out according to the procedure of Olson et al., Endocrinology 35, 40, 1944, 50 pig/rat, s.c., of the compound 1,4- pregnadiene-9a-fluoro-1 1,8,2 1 -diol-3 ,20-dione- :,17a-d]-2-methyloxazoline-2l-acetate was found to increase the liver glycogen from a value of about 1-2 to about 17-18. The values are expressed as mg. of glucose per 100 g. of body weight of the rats. The other compounds of this invention also show a comparable activity.

The following examples describe procedures used in preparations of representative compounds of this invention.

EXAMPLE 1 Sa-Pregnane- 1 6a, 1 7a-epoxy-3B-ol-1 1,20-dione To a solution of 150 g. of 5a-pregn-16-en-3B-ol- 1 1,20-dione-3-propionate in 3,500 ml. of tert-butanol, 75 g. of KOl-l dissolved in 600 ml. of water is added, and the mixture is refluxed for 2 hours in a nitrogen atmosphere. After cooling, 450 ml. of hydrogen peroxide, 35.5 percent w/v, is added and the mixture is stirred for 6 hours at room temperature. After addition of acetic acid to neutrality, the solvent is removed in vacuo and the residue is collected and dried. Yield 134.5 g. (100%), melting at 177-178C.

EXAMPLE 2 Sa-Pregnane-l6B-azido-3B,17B-diol-1 1,20-dione A mixture of 50 g. of Sa-pregnane-l6a,17a-epoxy- 3B-ol-l 1,20-dione 400 ml. of dimethylformamide, 7.15 g. of H 80 80 ml. of water and 75 g. of sodium azide is refluxed for 2 hours and, while still hot, a solution of 300 ml. of saturated aqueous sodium bicarbonate is added, followed by 1,700 ml. of water. After stirring for 1 hour, the precipitate is collected and dried. Yield 52 g. (92%) of the above-named product, melting at 22l223C, which is sufficiently pure for the subsequent step. A purified sample melts at 229-23lC, [11],, 114.3 cHc| EXAMPLE 3 Sa-Pregnanel 6B-azido-3B, l 7a-diol-l 1,20-dione- 3 ,17-diacetate A mixture of 250 g. of the crude 16/3-azido-steroid, prepared as in Example 2, 700 ml. of acetic acid, 550 ml. of acetic anhydride and 37 g. of p-toluenesulfonic acid is heated for 75 minutes on a water bath and then poured into 4,000 ml. of water. The collected diacetate is recrystallized from ethanol. Yield 216 g. (71%), melting at 204-206C, [041 37.5 (CHCl EXAMPLE 4 Sa-Pregnane-16B-amino-3/3,17a-diol-1 1,20-dione- 3,17-diacetate A mixture of 300 g. of the diacetate product of Example 3, 10,000 ml. of ethyl acetate and 300 g. of Raney nickel is hydrogenated under a hydrogen stream for hours, then the mixture is filtered and the filtrate is evaporated to a volume of about 8,000 ml. The precipitate is collected and dried. Yield 205 g. (72%), melting at l91195C, [01],, 22 (Cl-lCl EXAMPLE 5 Sa-Pregnanel 6B-chloroamino-3B, 1 7a-diol-l 1,20- dione-3,17-diacetate A mixture of 162 g. of the l6fi-amino steroid product of Example 4, 2,600 ml. of dichloromethane and 55 g. of N-chlorosuccinimide is stirred at room temperature for minutes, washed with water, dried over sodium sulfate and filtered. The filtrate is evaporated to dryness in vacuo. Yield, 135 g. (78%), melting at 176-18- 2C, [01],, 66.3(CHC1;,).

EXAMPLE 6 Sa-Pregn-l 5-enl 6-acetamido-3B, l 7a-diol-l 1,20- dione-3-acetate A mixture of 55 g. of the product obtained as in Example 5, 40.5 g. of potassium acetate and 500 ml. of dimethyl formamide is heated to 100C for 0.5 hour under nitrogen, cooled to about 40C and diluted with 2,500 ml. of water. The precipitate is collected, washed, dried and recrystallized from acetone. Yield 25 g. (49%), melting at 24 l -245C, [01],, 41.3 (CHCl EXAMPLE 7 Sa-Pregnanel 6a-acetamido-3B,l 7a-diol-1 1,20-dione- 3-acetate An amount of 50 g. of 5a-pregn-15-en-l6- acetamido-3B,l 7a-diol-1 1,20-dione-3-acetate and 12.5 g. of 10 percent palladium on charcoal in 2,000 ml. of acetic acid is hydrogenated for 3.5 hours, then filtered. The filtrate is evaporated to dryness, the residue is treated with aqueous sodium bicarbonate, collected, water-wahsed to removed sodium bicarbonate and dried. The crude product, consisting of a mixture of 1601- and l6fi-acetamido derivative, isdissolved in 1,200 ml. of hot methanol and filtered, the filtrate is concentrated to about 700 ml. and cooled. Yield 24 g. (48%), mp. 242246C, [01],, l4.5 (CHCl EXAMPLE 8 5a-Pregnane-3B-ol-l l,20-di0ne-[ l6a,l 7a-d]-2- methyloxazoline-3-acetate A mixture of 21.4 g. of 5oz-pregnane-1 6a-acetamido 3fl,l7a-diol-l 1,20-dionc-3-acetate, 10.7 g. of p-toluene-sulfonic acid, ml. of chloroform and 1,100 ml. of benzene is boiled until 200 ml. of liquid are distilled over, then refluxed for 1 hour and finally evaporated to dryness. The residue is dissolved in ethyl acetate, washed with aqueous sodium bicarbonate and with water and evaporated to dryness. Yield 12.5 g. (62%), mp 273-276C, [a],, 93.6 (CHCl EXAMPLE 9 5a-Pregnane-3B-ol-l l,20-dione-[ l6a,1 7a-d]-2'- methyloxazoline-3-acetate-20-semicarbazone To a boiling solution of 70 g. of 5a-pregnane-3/3-ol- 1 l,20-dione-[ 1601,17a-d]-2'-methyloxazoline- 3-acetate in 2,000 ml. of methanol is added a solution of 56 g. of semicarbazide hydrochloride, 41.3 ml. of pyridine and 350 ml. of water. The mixture is refluxed for 2 hours. After evaporation to dryness and addition of 2,000 ml. of water, the solids are collected and dried. Yield 77 g. (97%).

Example 10 5a-Pregnane-3B,l 1B-diol-20-one-l 16a,l 7a-d ]-2' methyloxazoline-3-acetate-20-semicarbazone To a solution of 77 g. of the semicarbazone prepared as in Example 9, dissolved in 2,000 ml. of ethanol, warmed and held at 60C in a nitrogen atmosphere is added a solution of 33 g. of potassium bicarbonate in 330 ml. of water followed by the portionwise addition of 20 g. of sodium borohydride. After refluxing for 40 minutes, an additional amount of 20 g. of sodium borohydride is added and refluxing is continued for 2 hours. After cooling, 210 ml. of acetic acid is gradually added to the reaction mixture and the ethanol is distilled off. The residual aqueous solution is neutralized with aqueous sodium bicarbonate and the precipitate is collected EXAMPLE 1 l oz-Pregn-9( l l )-en-3,6-ol-20-one-[ 16st,] 7a-d]-2- methyloxazoline A mixture of 93 g. of the semicarbazone prepared as in Example and 1,400 ml. of aqueous 25 percent hydrochloric acid is allowed to stand at room temperature for 22 hours, then made slightly alkaline by adding aqueous sodium hydroxide, extracted with chloroform, washed, dried and evaporated to dryness. The crude product (76.9 g.) is dissolved in hot chloroform, filtered after cooling and the filtrate is chromatographed through silica gel, using chloroform as the eluent. Yield 55 g. (71%), m.p. 208-21 1C, [a],, +64.8 (Cl-1C1 EXAMPLE l2 5a-Pregn-9(1 1)-en-3B-ol-20-one-21-iodo-[1611,1704- d]-2'-methyloxazoline To a mixture of 20 g. of 5a-pregn-9(1 1 )-en-3B-ol-20- one[16a,17a-d]-2-methyloxazoline, 0.4 g. of azo-bisisobutyronitrile, 30 g. of calcium oxide, 150 ml. of methanol and 150 ml. of tetrahydrofuran is added gradually a solution of 20 g. of iodine in 100 ml. of tetrahydrofuran and 60 ml. of methanol. The reaction mixture is stirred for 1 hour. The calcium oxide is filtered off, the filtrate is concentrated to about 100 ml., then a solution of g. of sodium bisulfite in 500 ml. of water is added, followed by 200 ml. of aqueous 5 percent acetic acid. The precipitate is collected and dried and passed in crude state to the subsequent step.

EXAMPLE l3 5a-Pregn-9( 1 l)-en-3B,2l-diol-20-one-[l6a,17a-d]-2'- methyloxazoline-2 1 -acetate The crude 21-iodo derivative of Example 12, dissolved in 500 ml. of acetone, is added to a previously prepared solution of 200 ml. of triethylamine in 55 ml. of acetone and 1 10 ml. of acetic acid, and the mixture is refluxed for 75 minutes. The acetone is then removed by distillation and 1,500 ml. of cold water is added. The precipitate is collected and dried. Yield 18 g. (78% calculated on the 2l-unsubstituted starting compound),

EXAMPLE l4 5a-Pregn-9( I l )-en-3 ,20-dione-21-ol-[ 1 611,1 7a-d]-2'- methyloxazoline-Z 1 -ace tate To a suspension of 36 g. of 5a-pregn-9(l1)-en- 3B- 21-diol-20-one-[ 16a,l7oz-d]-2 -methyloxazoline in 2,000 ml. of acetone, 30 ml. of 8N chromic acid is added, followed in 10 minutes by an additional 21.4 ml. of 8N chromic acid solution, then, 10 minutes later, by 1,000 ml. of water and, finally, by a solution of 30 g. of sodium bicarbonate in 1,000 ml. of water. The reaction temperature is always kept between 10 and 15C. After 0.5 hour about 500 ml. of acetone is distilled off in vacuo and the product precipitate is collected. A crude product is obtained which is dissolved in 800 ml. of hot acetone, filtered, the filtrate concentrated to about 150 ml. then diluted with 500 ml. of hexane. The resulting precipitated product is collected and dried. Yield 20.4 g. (64%), mp. 209- 214C, [01],, 53.4 (CHCl EXAMPLE 15 2,4-Dibromo-5a-pregn-9( 1 1 )-en-21-ol-3,20-dione- 16a, 1 7a-d]-2-methyloxazoline-2 1 -acetate To a solution of 4.2 g. of bromine in 60 ml. of dioxane add 8 ml. of a 26.3 percent hydrogen bromide solution in acetic acid followed by 5 g. of 5a-pregn-9( 1 1 en-3,20-dione-2 l -ol-[ 16a,l7a-d]-2-methyloxazoline- 21-acetate dissolved in ml. of dioxane. After being stirred 1 hour at room temperaure, the reaction mass is poured into 1,200 ml. of ice water containing 30 g. of sodium bicarbonate. The precipitate is collected and dried and used in the crude state for the following step.

EXAMPLE 16 1,4,9( 1 1 )-Pregnatriene-21 -ol-3,20-dione-[ 1 601,1 7a-d]- 2 -methyloxazoline-21-acetate The 2,4-dibromo product of Example 15 dissolved in 38.6 g. of dimethyl acetamide is added to a mixture, held at C, of 2.1 g. of lithium bromide, 4.05 g. of lithium carbonate and 58 ml. of dimethyl acetamide, and the mixture is heated for 12 hours under a nitrogen atmosphere. After cooling, the mass is poured into 1,000 ml. of a saturated sodium chloride solution and 40 ml. of acetic acid. After adjusting the suspension to pH about 7 with sodium bicarbonate, the precipitate is collected and dried. The product is purified by chromatography through silica gel in chloroform solution, m.p. l86l89C, [011 254 (CHCl EXAMPLE l7 1,4-Pregnadiene-9a-bromo-1 1,8,21-diol-3,20-dione- 16a,17a-d]-2'-methyloxazo1ine-21 acetate To 3 g. of 1,4,9(11)-pregnatrien-21-ol-3,20- dionel 1601,]7a-d]-2'-methyloxazoline-21 -acctate in 36 ml. of tetrahydrofuran, cooled at 5C, 15.2 ml. of 4.9 percent perchloric acid is added, followed by 1.32 g. of N-bromoacetamide. After stirring 4 hours at 5C, a 10 percent aqueous solution of sodium bisulfite is added, and the solution is diluted with 400 m1. of ice water. The resulting precipitate is collected and dried, then it is sludged with cold methanol. Yield 1.65 g.

EXAMPLE 18 1,4-Pregnadiene-9B,l 1,8-epoxy 21-ol-3 ,ZO-dione- 1 601,1 7a-d]-2'-methyloxazoline-2 l-acetate The 9a-bromo compound of Example 17 is refluxed for 10 hours with 66 ml. of acetone and 2.75 g. of potassium acetate. After cooling, water and chloroform are added and the chloroform layer is separated and evaporated to dryness. The residue is crystallized from a mixture of methanol and ethyl ether. Yield 0.46 g., m.p. l86189C, [02],, 77.3 (Cl- C1 EXAMPLE l9 1,4-Pregnadiene-9a-fluoro-l 13,31 -diol-3,20-dione- 16a,]7a-d1-2'-methyloxazoline-2l acetate At 70C, 6 g. of HF is dissolved in 10.85 ml. of tetrahydrofuran and to 3.67 ml. of this solution. 0.39 g. of 1 ,4-pregnadiene-9B,l lfi-epoxy-Z l -ol-3 ,ZO-dione- [l6a,]7a dl-2'-methyloxazoline-2l-acetate is added portionwise and the mixture is stirred 6 hours at room temperature. The mixture is then diluted with 6.25 g. of tetrahydrofuran, cooled to 0C and neutralized with a mixtureof 0.45 g. of sodium bicarbonate and 0.35 g. of sodium sulfate. The mass if filtered and the filtrate is evaporated to dryness in vacuo. The residue is dissolved in 20 ml. of acetone, filtered and the filtrate is concentrated to about 5 mLAfter addition of 8 ml. of hexane, the precipitate is collected and dried. Yield 9 0.22 g. (54%), m.p. 268270C, [a] 98.4 (CHCl Analysis for C H FNO percent: Calc. C, 65.35; H, 6.58; N, 3.05; Found C, 64.83; H, 6.79; N. 3.50.

I claim 1. A compound represented by the formula wherein X represents hydrogen or halogen, Y represents H(OH) or O, or X and Y together represent a double bond between the carbon atoms in 9 and l l positions, R represents hydrogen or lower acyl, and RIT represents lower alkyl.

2. The compound of claim 1 which is 1,4- pregnadiene-Qa-fluotO-l 1,8,2 1 -diol-3 ,20-dione- [1601, l 7a-d]-2'-methyloxazoline-2 l -acetate.

3. The intermediate for a compoundas claimed in claim 1 which is S-a-pregnane-l6a-acetamido3fl,l7adiol-l 1,20-dione-3-acetate.

4. Method for preparing a compound as claimed in claim 1 which comprises treating Sa-pregnane-I6B- chloroamino-3B, l 7a diol-l 1,20-dione-3, l 7-diacetate with potassium acetate in dimethylformamide whereby Sa-pregn-l S-en- 1 6-acetamido-3B, l 7a-di0l-l l ,20- dione-3-acetate is formed, hydrogenating the latter using palladiated charcoal as catalyst to give the 5apregnane-l6a-acetamido derivative, cyclizing the latter by refluxing a solution thereof in an aromatic hydrocarbon solvent to give 5a-pregnane-3B-ol-l 1,20-dione- [1601, l 7a-d1-2'-methyloxazoline-3-acetate, reducing the ll-keto group of the latter to an llfi-hydroxy group with sodium borohydride after first protecting the 20-keto group of the compound by forming the 2O- semicarbazone, hydrolyzing the ZO-semicarbazone compound with hydrochloric acid, the 3B-acylox'y group of said compound having been hydrolyzed during the previous alkaline reduction step to give a 3- hydroxy group whereby 5a-pregn-9( l l )-en-3B-ol20-one-[ l6a,l 7a-d1-2' -methyloxazoline is formed, iodinating the 2l-carbon atom of the latter in the presence of calcium oxide and azo-bis-isobutyronitrile followed by exchange between the 2l-iodo atom and acetate ion in the presence of triethylamine whereby the 2l-acetate compound is formed, oxidizing the latter with chromic acid to give the corresponding 3-keto compound, brominating the latter in positions 2 and 4, treating the latter with lithium carbonate in the presence of lithium bromide whereby l,4,9( l l )-pregnatriene-2 l -ol-3,20-dione- :,1 7a-d]-2'-methyloxazoline-2 l -acetate is obtained.

5. The method of claim 4 also including the step of treating the product l,4,9(ll)-pregnatriene with N- bromoacetamide and perchloric acid whereby 1,4- pregnadiene-9a-bromo-l 113,2 1 -diol-3,20-dione- 1 601,1 7a-d]-2'-methyloxazoline-2 l -acetate is formed.

6. The method of claim 5 also including the steps of dehydrohalogenating the product 9a-bromo-l 1B- hydroxy compound by refluxing it with potassium acetate in an anhydrous solvent to form the corresponding 93,1 lfl-epoxy compound and treating the latter with hydrogen fluoride to open the epoxy ring, whereby 1,4- pregnadiene-9a-fluoro-l 13,2 1 -diol-3,20-dione- 1601,] 7a-1-2 '-methyloxazoline-2 l -acetate is formed.

7. Method for making the compound of claim 3 which comprises treating 5a-pregnane-l6B-amino- 3B, 1 7a-diol-l 1,20-dione-3 l 7-diacetate with N- chlorosuccinimide to form the corresponding 16B- chloroamino compound, heating the latter in dimethyl formamide in the presence of potassium acetate whereby Sa-pregn-l S-enl 6-acetamido-3B,l 7a-dioll l,20-dione-3-acetate is formed and hydrogenating the latter using palladiated charcoal as catalyst whereby the compound of claim 3 is formed.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 .'755,303 Dated August 28, 1973 Invenwfls) G1 an giacnmo Nathansohn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

a Column 2, line 15, in the drawing, delete "C-O" and substitute C=O-.

Column 6, line 22, delete wahsed" and substitute -washed. line 40, delete "62%" and substitute Column 10, line 32, add -d after, l7oc.

Signed and sealed this 1st day of January 19714..

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents 

2. The compound of claim 1 which is 1,4-pregnadiene-9 Alpha -fluoro-11 Beta ,21-diol-3,20-dione-(16 Alpha ,17 Alpha -d)-2''-methyloxazoline-21-acetate.
 3. The intermediate for a compound as claimed in claim 1 which is 5- Alpha -pregnane-16 Alpha -acetamido-3 Beta ,17 Alpha -diol-11,20-dione-3-acetate.
 4. Method for preparing a compound as claimed in claim 1 which comprises treating 5 Alpha -pregnane-16 Beta -chloroamino-3 Beta ,17 Alpha -diol-11,20-dione-3,17-diacetate with potassium acetAte in dimethylformamide whereby 5 Alpha -pregn-15-en-16-acetamido-3 Beta ,17 Alpha -diol-11,20-dione-3-acetate is formed, hydrogenating the latter using palladiated charcoal as catalyst to give the 5 Alpha -pregnane-16 Alpha -acetamido derivative, cyclizing the latter by refluxing a solution thereof in an aromatic hydrocarbon solvent to give 5 Alpha -pregnane-3 Beta -ol-11,20-dione-(16 Alpha ,17 Alpha -d)-2''-methyloxazoline-3-acetate, reducing the 11-keto group of the latter to an 11 Beta -hydroxy group with sodium borohydride after first protecting the 20-keto group of the compound by forming the 20-semicarbazone, hydrolyzing the 20-semicarbazone compound with hydrochloric acid, the 3 Beta -acyloxy group of said compound having been hydrolyzed during the previous alkaline reduction step to give a 3-hydroxy group whereby 5 Alpha -pregn-9(11)-en-3 Beta -ol-20-one-(16 Alpha ,17 Alpha -d)-2''-methyloxazoline is formed, iodinating the 21-carbon atom of the latter in the presence of calcium oxide and azo-bis-isobutyronitrile followed by exchange between the 21-iodo atom and acetate ion in the presence of triethylamine whereby the 21-acetate compound is formed, oxidizing the latter with chromic acid to give the corresponding 3-keto compound, brominating the latter in positions 2 and 4, treating the latter with lithium carbonate in the presence of lithium bromide whereby 1,4,9(11)-pregnatriene-21-ol-3,20-dione-(16 Alpha ,17 Alpha -d)-2''-methyloxazoline-21-acetate is obtained.
 5. The method of claim 4 also including the step of treating the product 1,4,9(11)-pregnatriene with N-bromoacetamide and perchloric acid whereby 1,4-pregnadiene-9 Alpha -bromo-11 Beta , 21-diol-3,20-dione-(16 Alpha ,17 Alpha -d)-2''-methyloxazoline-21-acetate is formed.
 6. The method of claim 5 also including the steps of dehydrohalogenating the product 9 Alpha -bromo-11 Beta -hydroxy compound by refluxing it with potassium acetate in an anhydrous solvent to form the corresponding 9 Beta ,11 Beta -epoxy compound and treating the latter with hydrogen fluoride to open the epoxy ring, whereby 1,4-pregnadiene-9 Alpha -fluoro-11 Beta ,21-diol-3, 20-dione-(16 Alpha ,17 Alpha -)-2''-methyloxazoline-21-acetate is formed.
 7. Method for making the compound of claim 3 which comprises treating 5 Alpha -pregnane-16 Beta -amino-3 Beta ,17 Alpha -diol-11,20-dione-3,17-diacetate with N-chlorosuccinimide to form the corresponding 16 Beta -chloroamino compound, heating the latter in dimethyl formamide in the presence of potassium acetate whereby 5 Alpha -pregn-15-en-16-acetamido-3 Beta ,17 Alpha -diol-11,20-dione-3-acetate is formed and hydrogenating the latter using palladiated charcoal as catalyst whereby the compound of claim 3 is formed. 